Historically time of flight mass spectrometers have been employed due to their high mass accuracy, resolution and duty cycle. In addition to these benefits time of flight mass spectrometers also benefits from a large mass or mass to charge ratio range. The large mass range is useful for many applications.
However, there are some applications that are focused on measuring targeted subsets of the mass range, such as selected ion monitoring or recording (“SIR”) and multiple reaction monitoring (“MRM”). In these experiments the high resolution and mass accuracy of time of flight mass spectrometers is still of significant benefit in improving the specificity and/or selectivity of the measurement whereas the wide mass range is of limited use.
GB2486820 (“Micromass”) discloses a method of exploiting a restricted mass range entering the time of flight mass spectrometer to improve the duty cycle of the experiment, in order to improve the dynamic range and/or the sensitivity of the experiment.
US2014/0138526 (“Goldberg”) discloses a time of flight mass spectrometer.
WO2008/087389 (“Micromass”) discloses a mass spectrometer.
GB2505265 (“Micromass”) discloses multi-dimensional survey scans for improved data dependent acquisitions (DDA).
GB2396957 (“Franzen”) discloses a high resolution orthogonal acceleration TOF mass spectrometer with a high duty cycle.
U.S. Pat. No. 5,399,065 (“Myerholtz”) discloses sequencing ion packets for ion Time-of-Flight mass spectrometry.
WO2011/135477 (“Verenchikov”) discloses electrostatic mass spectrometer with encoded frequent pulses.
US2005/133712 (“Belov”) discloses scan pipelining for sensitivity improvement of orthogonal Time-of-Flight mass spectrometers,
Time of flight mass analysers typically use a pusher or acceleration electrode to accelerate groups of ions into a time of flight region.
It is desired to provide an improved mass spectrometer.